Hydraulic cylinder with an o-ring seal of variable geometry

ABSTRACT

A new system of hydraulic and piston cylinders for the lifting of large loads manufactured based on commercial tubes, in which the cylinder tube ( 1 ), closed on its lower part possesses a welded and rigid washer ( 2 ) on its lower part and inside the aforementioned cylinder. The piston has another rigid washer welded to it ( 4 ) at a certain distance from the lower end and on its outer surface. Between the two there is an O-Ring seal ( 6 ) of variable geometry that is constructed with an elastomeric, compressable and deformable material of low friction and high elasticity and a free washer. The compression of the O-Ring seal makes up a system that closes, guaranteeing its watertightness.

OBJECTIVE OF THE INVENTION

The objective of the invention consists of a new hydraulic cylindersystem equipped with a piston for the lifting of loads constructed withan O-Ring seal of variable geometry and with low-cost commercial tubingand which allows for the lifting or pushing of any load.

BACKGROUND OF THE INVENTION

Is it known that with a hydraulic cylinder, large loads can be lifted bysimply introducing pressure through a hydraulic fluid through the baseof the piston, which makes it move upwards or horizontally, making itpossible to carry out pushing or pulling actions. However, asextraordinarily useful as these hydraulic cylinders are, they requiresteel tubing that is calibrated with surfaces protected as much on theinner surface as on the outer surface to avoid friction. In normalindustrial applications, hydraulic cylinders are always reusable manytimes over, something for which industry can pay for a system thatrequires precision tubing calibrated and rectified and even with ananti-friction inner coating, which covers for the high costs with a veryhigh level of re-use. However, in appliances of very large dimensions,and of one sole use or of several uses, and in those in which the thecylinders are part of the permanent structure of the installations, likeoceanic platforms [rigs] or installations in the sea, for them to bekept afloat, for pile driving, etc, the use of calibrated andstraightened tubes would bring with it a very high cost which wouldrender the system unviable. For this, it is necessary to design aneconomically viable alternative which would permit the carrying of largesized loads. For this, this invention describes a hydraulic cylinderwhich involves a piston consistent with those used in commercial tubes,a low cost one which has an O-Ring seal of determinate characteristicsinserted into it.

A commercial tube, unlike a calibrated and straightened tube, hasuniversally accepted tolerances in its thickness, radius, and ovality.Variable tolerances are accepted up to a certain level. Hence, if thetube has a tolerance and the piston also has one, it would be impossibleto make, with techniques known up to now, an O-Ring seal which wouldguarantee watertightness with that difference in dimensions. What makesthe process more complex is that the coating tolerances are notcontinuous, in other words, at the end of a tube, there can be oneradial tolerance and in the centre there can be another radialtolerance, or that the ovality can be different at the end than in thecentre, hence, it is necessary to develop an O-Ring seal that wouldpermit the use of low cost commercial tubes, thus solving theaforementioned problems of viability.

DESCRIPTION OF THE INVENTION

This invention consists of a tube which we shall call a cylinder tubewhich closes at the bottom to become a watertight chamber. This cylindertube bears a welded and rigid washer on the upper part inside the saidcylinder. Another tube, which is a piston, introduced inside thecylinder tube, is open on its lower part and, a certain distance fromits lower end, has another rigid washer, welded and with threaded drillholes around its whole edge, similar to that of the cylinder tube, butwelded on the exterior of the piston.

The tubes used are commercial tubes, of lower cost than calibratedstraightened tubes.

Beneath the soldered washer, the piston has an O-Ring seal of variablegeometry with through bores introduced into it, which is constructed ofan elastomeric compressable and deformable material of low friction andhigh elasticity. The joint does not touch the cylinder tube but ratherthere remains a certain looseness. Under the O-Ring seal another washeris placed, which will be loose and with bores in line with those of thefixing. The O-Ring seal, compresses up to a predetermined pressure andwhich guarantees that it will adapt in full to the relative variationsof the cylinder and of the piston in compressing itself through theturning of the taps, up to the predetermined pressure, changing shapeand adapting until it closes up completely.

The way the hydraulic cylinder with drill holes in the washers and inthe O-Ring seal functions will be explained further on.

Bolts are then put into the washer, which cross go through the O-Ringseal and the washer welded to the piston and they start to grip up tothe point where the grip pressure is what has been determined.

Whilst the seal is not touching the wall of the tube of the cylinder,there is no grip resistance, because the seal, being elastic, starts todeform. When the seal then touches the inner wall the bolts continue tobe tightened up to the point that the seal closes completely.

The loose washer has an indeterminate number of holes, which there willbe more of depending on the diameter of the tube. Its function is tocompress and adjust the seal.

The bolts are not tightened simultaneously, but rather one by one, insuch a way that when the bolt reaches the determined pressure, wetighten the other(s) and so on, successively. In this way, if there aredifferences of radius or ovality in one place or another, we can resolveit by suitably adjusting each bolt.

This system allows for a telescopic series of the desired sizes, thepiston tube simply becomes the cylinder tube of another more internaltube and each tube has a rigid washer welded on the upper and inner partof itself, just as the more external tube and the inner tubes would havethe washer welded at a certain distance from its base, the O-Ring sealand the loose washer.

DESCRIPTION OF THE FIGURES

To complete the description being given here and with the aim of aidingbetter understanding of the characteristics of the invention, there is adiagram where, in an illustrative and not limitative way, the followinghas been represented:

FIG. 1: View of a vertical section of the hydraulic cylinder with avariable O-Ring seal

What follows below is the provision of a list with the reference numbersused in the—figures:

1.—Cylinder tube

2.—Welded washer on the cylinder tube

3.—Piston

4.—Washer welded to the piston

5.—Bores

6.—O-Ring seal

7.—Loose washer

DETAILED DESCRIPTION OF THE INVENTION

To manage to have a better understanding of the invention whosedescription follows below, with the aid of the figures, the newhydraulic cylinder and lifting piston constructed with an O-Ring seal ofvariable geometry.

The cylinder tube (1) closed in its lower part presents a rigid washer(2), welded on the upper part of the tube and to its own inside. Thelifting piston (3), situated inside the cylinder tube (1), is open atthe bottom and, at a certain distance from the lower end, presentsanother welded rigid washer (4), but on the outer surface of the piston.This washer presents a series of bores around it (5). Under the washer(4) welded to the piston, an O-Ring seal is placed (6), which has acertain looseness, with the same number and position of bores as thewasher of the (4) piston. This washer is made of an elastomeric materialof low friction and high elasticity. Under the O-Ring seal, anotherwasher is placed (7) which will be loose. This loose washer also hasbores for the introduction of bolts.

The bolts are tightened to the point that the seal compresses enough toclose the space completely. The hydraulic fluid used can also help tocompress the seal.

1. A hydraulic cylinder with an O-Ring seal of variable geometry for thelifting or pushing of any load characterised by comprising of: Acylinder tube (1) closed on its inside that is equipped with a weldedrigid washer (2) in the upper and inner parts of said cylinder, A piston(3) which at a certain distance of its lower end and on its outersurface has another rigid washer welded to it (4), An O-Ring seal (6) ofvariable geometry which is constructed of an elastomeric, compressibleand deformable material, of low friction and high elasticity situatedbetween the cylinder tube and the piston and One loose washer (7)between the cylinder tube and the piston, With (1) being the cylindertube and (3) being the piston and commercial pipelines.
 2. The hydrauliccylinder in patent claim 1, is claimed because the washer (4) welded tothe piston, the O-Ring seal (6) and the free washer (7) present somebores (5) for the insertion of bolts that allow for the tightening andcompression of the O-Ring seal (6).
 3. Hydraulic cylinder in patentclaim 2, is claimed because it comprises of a series of bolts tocompress the O-Ring seal (6).
 4. O-Ring seal (6) of variable geometrythat is constructed of an elastomeric, compressable and deformablematerial of low friction and high elasticity for its use in thehydraulic cylinder from patent claim 1.